While spacecraft can use stars to get a sense of direction, figuring out how far and where a spacecraft has traveled from home usually requires accurate radio tracking from Earth. But members of NASA’s New Horizons team – using the mission’s spacecraft, now more than five billion miles from Earth – have demonstrated for the first time that it’s possible to determine direction and distance just by examining images the spacecraft snaps of star fields.

“As a spacecraft travels deeper into space, the positions of the stars seen from its location begin to shift from where they are seen from Earth,” explained Tod Lauer, an astrophysicist and New Horizons science team member from the National Optical-Infrared Astronomy Research Laboratory in Tucson, Arizona. “A spacecraft voyaging out into the Milky Way can measure these shifts, due to an effect called parallax, to locate where it is with respect to nearby stars. New Horizons has traveled far enough away that it can provide the first true demonstration of interstellar navigation.”